Lifting jack



J. A.. moamson. LIFUNG ck. APPLICATION FILED FEB- 24 [92L 1,428,702. PatenredSept. 12, 1922,

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JOHN MORRISON, 0F MANSFIELD. OHIOv LIFTING- JACK.

i aclcs especially adapted for use in connection with heavy automobile trucks, and pertains more particularly to a jack of this character comprising high and low speed mechanism.

The objects of the present invention are to provide a jack of the character above referred to in which high and low speed mechanism is provided whereby an increased: load may be raised without any increase power by operating the low speed drive.

The above, together with other objects may be attained by providing a pair of shafts for selective reception of the socket of the usual handle by means of which the jack is raised, one of said shafts being directly connected to the raising mechanism and provided for a high speed and the other shaft being connected to the raising mechanism by gearing providing a low speed.

W'ith these objects in view, the invention consists in the construction and arrangement of parts hereinafter described and illustrated in the accompanying drawings. it being understood that changes in the form, proportion and details of construction may be made within the scope of the appended claims.

The invention thus set forth in general terms is illustrated. in the accompanying drawings forming part hereof, in which Figure 1 is a side elevation of a lifting jack embodying the invention, a part of the gear housing being broken away for the purpose of illustration.

Fig. 2 is a front view of the jack with the housing broken away, the drive worm being shown in section.

Fig. 3 is a section on the line 3-S, Fig. 1 upon an enlarged scale, and

Fig. 4 is an elevation partly in section. of a portion of the operating handle.

Similar numerals of reference indicate corresponding parts throughout the several figures of the drawing.

The standard within which the lifting mechanism is carried, comprises a housing 1 which may be skirted as shown at 2 to Application filed February 24:, 1921. Serial No. 447,474.

provide a substantial support, the base of the housing being closed as indicated at 3 in order to prevent dirt and dust from entering the housing and settling upon the working parts of the mechanism.

The lifting bar 1 of the jack comprisesa rack vertically slidably mounted within the housing and n'ieshing with the pinion 5 which is lined upon theshaft 6 uponwhich shaftis also fixed the worm gear 7, which meshes with the worm 8, a suitable gear housing 9 being provided to accommodate the worm gear and worm.

A ball bearing 10 may be provided upon the shaft 11 of the worm to allow for a free movement of the worm and to take up the end thrust of the shaft, the outer extremity of said shaft being squared at 12 for the reception of the socket 23 of the usual handle 24 by means of which the worm may be rotated to operate the raising mechanism.

A gear housing 13 is mounted upon the housing of the jack, being preferably connected to the gear housing 9 and encloses the large internal gear 1 1 which is fixed upon the shaft 11 and meshes with the pinion 15, said pinion being fixed upon a shaft 16 journaled in a bearing 17 formed in the cover plate 18 of the housing, said shaft being provided with a squared portion 19 for the reception of the socket of the handle 24.

A. head 20, provided with a corrugated or serratedupper surface 21, is loosely m0unted upon the upper end of the lifting bar by means of a pin 2-2, this head being provided for engagement with the under surface of the automobile axle or other portion of the automobile beneath which the jack may be conveniently placed for the purpose of raising the automobile.

In operating the jack, if thesocket of the handle 24: is engaged with the squared portion of the shaft 11, it will be seen that a direct drive is produced, the lifting. bar being raised rapidly. When the jack is used beneath a light or unloaded truck, this high speed lift is preferable, as suflicient power is developed through the worm gearing to easily raise the load.

However, if the jack is placed beneath a heavy or loaded truck, it will'be seen that a greater amount of power must necessarily be applied to the shaft 11 and for this purpose the socket of the operating handle 24 is engaged with'the squared shank of the shaft 16, driving the shaft 11 through the pinion 15 and internal gear 14, raising the lifting bar at a slower speed or performing the operation with substantially the same amount of power which is required in raising the lighter load.

As the gearing is about three and onehalf to one, it will be seen that about three and one-half times the minimum load may be raised with the low speed with the minimum power.

I claim 1. A lifting jack provided with a standard containing lifting mechanism, a rotatable shaft provided with a worm engaging the lifting mechanism and having a squared portion, an internal gear fixed upon said shaft, a pinion meshing with said internal gear, a shaft upon which the pinion is fixed,

said last named shaft provided with a squared portion and an operating handle provided with a socket interchange-ably mountable upon said squared portions.

2. A lifting jack provided with a stand ard containing a sliding rack bar, a pinion engaging the rack bar, a worm gear fixed to the pinion, a rotatable shaft provided with a worm engaging the worm gear and having a squared portion, an internal gear fixed upon said shaft, a pinion meshing with said internal. gear a shaft upon which the pinion is fixed, said last named shaft provided with a squared portion and an operating handle provided with a socket interchangeably mountable upon said squared portions. In testimony that I claim the above, I have hereunto subscribed my name.

JOHN A. MORRISON. 

